This invention relates to refrigerated display cases, and closed display cases as of the deli service type.
Closed refrigerated display cases, because of the cool air inside the case, tend to collect condensed moisture on the glass window used to display the food products, i.e., the windows tend to "sweat." Condensation moisture on the inner surface can be prevented by circulating refrigerated air within the case, the moisture being picked up and condensed on the refrigeration coil used to cool the air. As to the exterior surface of the display window, the typical technique for preventing/removing condensation is to warm the window with added heat. This can be heat applied directly to the window, or heat applied to a portion of the flowing air in the cabinet, causing the heated air portion to flow across the window inner surface to warm the window. An example of the use of a heater placed in the air stream for this purpose is shown in U.S. Pat. No. 4,750,335. While application of heat is effective, it requires use of extra energy to create the heat, and then more energy for extra cooling action to again cool the heated air for preventing unwanted temperature rise within the cabinet display area and the stored food.